 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.keys;

 import java.util.Arrays ;
 import java.util.Collections ;
 import java.util.Set ;
 import java.util.SortedSet ;
 import java.util.StringTokenizer ;
 import java.util.TreeSet ;

 import org.eclipse.ui.internal.util.Util;

 /**
  * <p>
  * A <code>KeyStroke</code> is defined as an optional set of modifier keys
  * followed optionally by a natural key. A <code>KeyStroke</code> is said to
  * be complete if it contains a natural key. A natural key is any Unicode
  * character (e.g., "backspace", etc.), any character belonging to a natural
  * language (e.g., "A", "1", "[", etc.), or any special control character
  * specific to computers (e.g., "F10", "PageUp", etc.).
  * </p>
  * <p>
  * All <code>KeyStroke</code> objects have a formal string representation
  * available via the <code>toString()</code> method. There are a number of
  * methods to get instances of <code>KeyStroke</code> objects, including one
  * which can parse this formal string representation.
  * </p>
  * <p>
  * All <code>KeyStroke</code> objects, via the <code>format()</code> method,
  * provide a version of their formal string representation translated by
  * platform and locale, suitable for display to a user.
  * </p>
  * <p>
  * <code>KeyStroke</code> objects are immutable. Clients are not permitted to
  * extend this class.
  * </p>
  *
  * @deprecated Please use org.eclipse.jface.bindings.keys.KeyStroke
  * @since 3.0
  * @see org.eclipse.ui.keys.ModifierKey
  * @see org.eclipse.ui.keys.NaturalKey
  */
 public final class KeyStroke implements Comparable {

     /**
      * The delimiter between multiple keys in a single key strokes -- expressed
      * in the formal key stroke grammar. This is not to be displayed to the
      * user. It is only intended as an internal representation.
      */
     public final static String KEY_DELIMITER = "\u002B"; //$NON-NLS-1$

     /**
      * An internal constant used only in this object's hash code algorithm.
      */
     private final static int HASH_FACTOR = 89;

     /**
      * An internal constant used only in this object's hash code algorithm.
      */
     private final static int HASH_INITIAL = KeyStroke.class.getName()
             .hashCode();

     /**
      * The set of delimiters for <code>Key</code> objects allowed during
      * parsing of the formal string representation.
      */
     public final static String KEY_DELIMITERS = KEY_DELIMITER;

     /**
      * Gets an instance of <code>KeyStroke</code> given a single modifier key
      * and a natural key.
      *
      * @param modifierKey
      * a modifier key. Must not be <code>null</code>.
      * @param naturalKey
      * the natural key. May be <code>null</code>.
      * @return a key stroke. Guaranteed not to be <code>null</code>.
      */
     public static KeyStroke getInstance(ModifierKey modifierKey,
             NaturalKey naturalKey) {
         if (modifierKey == null) {
             throw new NullPointerException ();
         }

         return new KeyStroke(
                 new TreeSet (Collections.singletonList(modifierKey)), naturalKey);
     }

     /**
      * Gets an instance of <code>KeyStroke</code> given an array of modifier
      * keys and a natural key.
      *
      * @param modifierKeys
      * the array of modifier keys. This array may be empty, but it
      * must not be <code>null</code>. If this array is not empty,
      * it must not contain <code>null</code> elements.
      * @param naturalKey
      * the natural key. May be <code>null</code>.
      * @return a key stroke. Guaranteed not to be <code>null</code>.
      */
     public static KeyStroke getInstance(ModifierKey[] modifierKeys,
             NaturalKey naturalKey) {
         Util.assertInstance(modifierKeys, ModifierKey.class);
         return new KeyStroke(new TreeSet (Arrays.asList(modifierKeys)),
                 naturalKey);
     }

     /**
      * Gets an instance of <code>KeyStroke</code> given a natural key.
      *
      * @param naturalKey
      * the natural key. May be <code>null</code>.
      * @return a key stroke. This key stroke will have no modifier keys.
      * Guaranteed not to be <code>null</code>.
      */
     public static KeyStroke getInstance(NaturalKey naturalKey) {
         return new KeyStroke(Util.EMPTY_SORTED_SET, naturalKey);
     }

     /**
      * Gets an instance of <code>KeyStroke</code> given a set of modifier
      * keys and a natural key.
      *
      * @param modifierKeys
      * the set of modifier keys. This set may be empty, but it must
      * not be <code>null</code>. If this set is not empty, it
      * must only contain instances of <code>ModifierKey</code>.
      * @param naturalKey
      * the natural key. May be <code>null</code>.
      * @return a key stroke. Guaranteed not to be <code>null</code>.
      */
     public static KeyStroke getInstance(SortedSet modifierKeys,
             NaturalKey naturalKey) {
         return new KeyStroke(modifierKeys, naturalKey);
     }

     /**
      * Gets an instance of <code>KeyStroke</code> by parsing a given a formal
      * string representation.
      *
      * @param string
      * the formal string representation to parse.
      * @return a key stroke. Guaranteed not to be <code>null</code>.
      * @throws ParseException
      * if the given formal string representation could not be
      * parsed to a valid key stroke.
      */
     public static KeyStroke getInstance(String string) throws ParseException {
         if (string == null) {
             throw new NullPointerException ();
         }

         SortedSet modifierKeys = new TreeSet ();
         NaturalKey naturalKey = null;
         StringTokenizer stringTokenizer = new StringTokenizer (string,
                 KEY_DELIMITERS, true);
         int i = 0;

         while (stringTokenizer.hasMoreTokens()) {
             String token = stringTokenizer.nextToken();

             if (i % 2 == 0) {
                 if (stringTokenizer.hasMoreTokens()) {
                     token = token.toUpperCase();
                     ModifierKey modifierKey = (ModifierKey) ModifierKey.modifierKeysByName
                             .get(token);

                     if (modifierKey == null || !modifierKeys.add(modifierKey)) {
                         throw new ParseException(
                                 "Cannot create key stroke with duplicate or non-existent modifier key: " //$NON-NLS-1$
 + token);
                     }
                 } else if (token.length() == 1) {
                     naturalKey = CharacterKey.getInstance(token.charAt(0));
                     break;
                 } else {
                     token = token.toUpperCase();
                     naturalKey = (NaturalKey) CharacterKey.characterKeysByName
                             .get(token);

                     if (naturalKey == null) {
                         naturalKey = (NaturalKey) SpecialKey.specialKeysByName
                                 .get(token);
                     }

                     if (naturalKey == null) {
                         throw new ParseException(
                                 "Cannot create key stroke with invalid natural key: " //$NON-NLS-1$
 + token);
                     }
                 }
             }

             i++;
         }

         try {
             return new KeyStroke(modifierKeys, naturalKey);
         } catch (Throwable t) {
             throw new ParseException("Cannot create key stroke with " //$NON-NLS-1$
 + modifierKeys + " and " + naturalKey); //$NON-NLS-1$
 }
     }

     /**
      * The cached hash code for this object. Because <code>KeyStroke</code>
      * objects are immutable, their hash codes need only to be computed once.
      * After the first call to <code>hashCode()</code>, the computed value
      * is cached here for all subsequent calls.
      */
     private transient int hashCode;

     /**
      * A flag to determine if the <code>hashCode</code> field has already
      * been computed.
      */
     private transient boolean hashCodeComputed;

     /**
      * The set of modifier keys for this key stroke.
      */
     private SortedSet modifierKeys;

     /**
      * The set of modifier keys for this key stroke in the form of an array.
      * Used internally by <code>int compareTo(Object)</code>.
      */
     private transient ModifierKey[] modifierKeysAsArray;

     /**
      * The natural key for this key stroke.
      */
     private NaturalKey naturalKey;

     /**
      * Constructs an instance of <code>KeyStroke</code> given a set of
      * modifier keys and a natural key.
      *
      * @param modifierKeys
      * the set of modifier keys. This set may be empty, but it must
      * not be <code>null</code>. If this set is not empty, it
      * must only contain instances of <code>ModifierKey</code>.
      * @param naturalKey
      * the natural key. May be <code>null</code>.
      */
     private KeyStroke(SortedSet modifierKeys, NaturalKey naturalKey) {
         this.modifierKeys = Util.safeCopy(modifierKeys, ModifierKey.class);
         this.naturalKey = naturalKey;
         this.modifierKeysAsArray = (ModifierKey[]) this.modifierKeys
                 .toArray(new ModifierKey[this.modifierKeys.size()]);
     }

     /**
      * @see java.lang.Comparable#compareTo(java.lang.Object)
      */
     public int compareTo(Object object) {
         KeyStroke castedObject = (KeyStroke) object;
         int compareTo = Util.compare(modifierKeysAsArray,
                 castedObject.modifierKeysAsArray);

         if (compareTo == 0) {
             compareTo = Util.compare(naturalKey, castedObject.naturalKey);
         }

         return compareTo;
     }

     /**
      * @see java.lang.Object#equals(java.lang.Object)
      */
     public boolean equals(Object object) {
         if (!(object instanceof KeyStroke)) {
             return false;
         }

         KeyStroke castedObject = (KeyStroke) object;
         
         if (!modifierKeys.equals(castedObject.modifierKeys)) {
             return false;
         }
         return Util.equals(naturalKey, castedObject.naturalKey);
     }

     /**
      * Formats this key stroke into the current default look.
      *
      * @return A string representation for this key stroke using the default
      * look; never <code>null</code>.
      */
     public String format() {
         return KeyFormatterFactory.getDefault().format(this);
     }

     /**
      * Returns the set of modifier keys for this key stroke.
      *
      * @return the set of modifier keys. This set may be empty, but is
      * guaranteed not to be <code>null</code>. If this set is not
      * empty, it is guaranteed to only contain instances of <code>ModifierKey</code>.
      */
     public Set getModifierKeys() {
         return Collections.unmodifiableSet(modifierKeys);
     }

     /**
      * Returns the natural key for this key stroke.
      *
      * @return the natural key. May be <code>null</code>.
      */
     public NaturalKey getNaturalKey() {
         return naturalKey;
     }

     /**
      * @see java.lang.Object#hashCode()
      */
     public int hashCode() {
         if (!hashCodeComputed) {
             hashCode = HASH_INITIAL;
             hashCode = hashCode * HASH_FACTOR + modifierKeys.hashCode();
             hashCode = hashCode * HASH_FACTOR + Util.hashCode(naturalKey);
             hashCodeComputed = true;
         }

         return hashCode;
     }

     /**
      * Returns whether or not this key stroke is complete. Key strokes are
      * complete iff they have a natural key which is not <code>null</code>.
      *
      * @return <code>true</code>, iff the key stroke is complete.
      */
     public boolean isComplete() {
         return naturalKey != null;
     }

     /**
      * Returns the formal string representation for this key stroke.
      *
      * @return The formal string representation for this key stroke. Guaranteed
      * not to be <code>null</code>.
      * @see java.lang.Object#toString()
      */
     public String toString() {
         return KeyFormatterFactory.getFormalKeyFormatter().format(this);
     }
 }

